Dynamo-electric machine.



J. L. BURNHAM. DYNAMO ELECTRIC MACHINE. APPLICATION FILED 001326, 1910.

2 SHEETSSHEET 1.

Patented Mar. 11, 1913.

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Es ATTQHNEY Patented Mar. 11, 1913.

UNITED STATES PATENT OFFICE.

JOSEPH L. BURNHAM, OF SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELEC- TRIC COMPANY, A CORPORATION OI! NEW YORK.

DYNAMO-ELECTRIC MACHINE.

To all whomdt may concern:

Be it known that I, JOSEPH L. BURNHAM,

a citizen-of the United States, residing at Schenectady, in the county of Schenectady, 'State of New York, have invented certain new I and useful Improvements in Dynamo-Electric Machines, of which the, following is a specification.

My invention relates to dynamo-electric machines, and particularly to such machines provided with anti-sparking windings.

The object of my invent-ion is to arrange the anti-sparking windings so that they will always be of the proper strength to produceflux may vary while the armature current Y lish itself across the brushes, this diiference of 'vo-ltageacts on a corrective device which remains constant and, therefore ,does not produce a corresponding corrective change in the anti-sparking windings or in the flux produced by them. Also in all dynamo-- electric machines provided with commutat ing poles the proportionality between the variations'in the armature current and the.

magnetic flux under the commutating pole is likewise disturbed as the load is increased due to the fact that the magnetization of the commutating pole is ator past -the'knee in the saturation curve. With inlng windings is varied in accordance with the variations'xof differences of voltage from heel to toeof the brushes. As soon as a difference of voltage greater than some predetermined negligible value tends to estabreadjusts the excitation of the anti-sparking windings. As will be more fully. eX-. lfilained in connection with the accompany Specification of Letters Patent Patented Mar. 11, 1913.

Application filed October 26, I910. Serial No. 589,219.

ing drawings, I provide anti-sparking windings and control the current in said windings by a device responsive toa difference of potential between the heel and toe of the brushes. P

'In the drawings, Figure 1 shows diagrammatically a regulating pole, or variable rat-1o rotary converter, and Fig. 2 shows an ordinary commutating pole machine both being provided with anti-sparking windings in accordance with my invention.

Referring to Fig. 1, the armature 1 of the rotary takes current from alternating current supply lines 2 connected thereto by' means of slip rings 3' in the usual manher. On the direct current side of the machine the main brushes 4', 5 are connected, as will be presently explained, to the direct current supply lines 6, 7, The windings 9, 10 0n the. main poles are connectedinseries by means of conductors 11, 12, across the lines 6, 7 through a switch 1?: and in series with an adjustable rheostat 14-. The regulating poles have their windings, 15, 16 con-.- nected in series across lines 6, 7 by means of conductors 17, 18 in which is'included art adjustable rheostat 19 and a reversing switch.

v20. The commutating poles 21, 22- are each' ,occur and provided the iron of the magnetic circuit did not become saturated as its excitation increased. In order to produce the additional excitation which isnecessary to compensate for disturbances resulting from the variations in flux of the regulat ing poles, or the saturation of the iron, the

"commutating poles are provided with auxiliary anti-sparking windings 29, 30, con nected in shunt across the lines 6, in series with a resistance 31. The circuit is com-- 30, conductor 34 and conductor. 27 which connected to line 7. The resistance s shunted by conductors 35, 36 in the circuit pleted through conductor 32 connec tedi to line 6, winding 29,"co'n"ductor"33; winding of which is includcda vibratingcontact' irg.

This vibrating contact is controlled-i by switch 38 which. is connected za magnet' 39 working against a springAOQ m a'zmanner which is well understood gin.connection with the Operation of thejifirrillglegiflator,"

which I have shown diagrainmati cailyi The winding of the magnet 39 is, connected by means of conductors-A1,,42 tofauxiliary These'auxiliarybrushes may be placed at some slight distance from the main-brush.

The operation of the system just .de-i scribed is "as follows When the voltage from heel to"toe of the brushes does not exceed a certainpredetermined value, the contact 37 remains open. This predetermined value of voltage may be as much as one volt without causing sparking. If anything ocours to cause the commutating field to vary in such a manner as to increasethis voltage, as for example, by varyingor reversing the excitation of the regulating poles 15, 16 in order to vary the ratio between the direct and alternating currents, or by the magnetic circuit becoming saturated,a current will circulate through the winding 39 which is great enough to close contact 37, thereby short-circuiting the resistance 31 because of the increased difference of potential beence of potential between the auxiliary or exploring brushes has been reduced, thereby weakening the pull of the magnet '39 until the contact 37 is opened by the pull of the spring 40. As the voltage again tends to rise, this cycle of operation will be repeated,

the vibration taking place at a high rate of speed and the relative lengths of time that the resistance 31 is inserted or withdrawn depending upon the value of the potential which under. the conditions tends to establish itself from heel to toe across the direct currentbrushes. The rapid insertion and withdrawal of'the resistance 31in the circuit of windings 29,30 maintainsthe excitation of these windings at a value necessary to produce a proper commutating field and prevent sparking at the brushes.

Fig. 2 illustrates diagrammatically an ordinary commutating pole machine having its armature 45 connected across lines 46, 47,;by means of brushes 48, 49, the circuit connections being traced hereinafter.

The windings 51, 52, on .the main polesarc;

connected in series by means of conductors 53, 54, acroslines $6, 47 th enetic in eluding an-, .adjustab'le. rhwstat; 551-Jand a switch 56; y The 57, 5'8 are provided withsanti-sparking' .windings; 59, 60, respectively, these windings .being connected in series'With the brushes,f the.cir-

cuit being completed from brush 48 through conductor 61,- winding. =69, conductor 62, winding 60, conductor-63, which is connected to line 47, the -circuit being completed from 'line' 46 through conductor '65Ywhich returns tothe brush 49. "As in 1, the

series windings on the commutating poles may be calculated togive a maximum excitat-ion corresponding to the minimum ratio of ampere turns to load, but instead ofcalculating the series windings for the mini-' mum ratio Ofampere turns to load, in, the

arrangementshown in this figure'theyhare calculated for. a greater number'of ampere turns than this. In this case, it will be nec{ essary to reverse as well as to regulate the strength of the current flowing through the auxiliary windings 66, 67 on the commu: tating poles in order to produce the proper commutating field for varying loads on the machine. The auxiliary antisparking windings 66, 67 are connected across the lines 46, 47, the circuit being completed through conductors 68, resistance 69, con

ductor 70, the contacts of a reversing switch 4 controlled by the polarized relay 71, conductor 72, winding 66, conductor73, wind ing 67, conductor 74,- a second set of con tacts of the reversing switch and conductor. 75. As already explained in connection with Fig. lthe au xiliary brushes 76, 77 are preferably insulated from the main brush. They are connected to the winding ofmag net 80 by means of conductors 81. The magnet 78 controls a vibrating contact 79 which periodically short-circuits the resistance 69 in the manner already explained. The short-circuiting device is shown dia-. grammatically and is preferably a Tirrill regulator.

The operation of the apparatus just described is similar to that'already described in connection with Fig. 1. If the magnetic circuit becomes saturated at high load values, the reversing switch takes the posi-' tion shown in the drawings, the auxiliary anti-sparking windings'assisting the series windings, and the contact 79 will vibrate at a high rate of speed to shortcircuit the resistance 69, in the circuit of the anti-sparking windings 66, 67, the relative lengths of ized relay which is connected across the conductor 81, thereby reversing the connections of the auxiliary windings 66, 67, so that the flux produced by these windings will now oppose the flux produced by the main windings 59, 60, thereby producing a resultant commutating flux of proper value, the contact 7t) vibrating as described before to regulate the current flowing through the wind- ,.mgs 66, 67 until the load falls so low that the voltage from heel to toe of the brushes does not exceed a certain predetermined value and the contact 79 remains open. Instead of calculating the series anti-sparking 5 windings to give a maxin. um excitation corresponding to the minimum ratio of ampere turns to load or for a somewhat greater number of turns than this, as explained in connection with Figs. 1 and 2, I may calculate the series anti-sparking windings for the maximum ratio of ampere turns to load, in which case the auxiliary anti-sparking windings will always oppose the series winding. In this case the polarized reversing switch of Fig. 2 is not needed. This combination is particularly desirable with rapidly changing loads as it. will establish the required commutating field more quickly.

I do not desire to limit myself to the particular arrangement here shown as changes which do not depart from the spirit of my invention and are within the scope of the appended claims, will be obvious to those skilled in the art. For example, the commutating poles may be provided with shunt windings only, the series windings being entirely dispensed with and the proper excitation of the shunt windings being maintained by the vibrations of the switch controlled by the voltage from heel to toe of the brush, thereby inserting and withdrawing the resistance in series with the shunt windings at proper intervals in order to maintain the anti-sparking field at the proper value. 4.5 What I claim as new and desire to secure -by Letters Patent of the United States is:

1. In a dynamo electric machine, an armature winding provided with a commutator, brushes on said commutator, antisparking windings connected in series with said armature winding, auxiliary antisparking windings, and meant for varying the excitation of said auxiliary windings in accordance with a difference of voltage from heel to toe of said brushes. v

2. In a dynamo electric machine, an armature winding provided with a commutator, brushes for said commutator, anti-sparking windings, auxiliary anti-sparking windings, and means for varying the polarity and effective ampere turns of said auxiliary windings in accordance with a diiierence in potential from heel to toe of any one of said brushes.

5 a dynamo electric machine, an arma ture winding provided with a commutator, brushes carrying the load current of said machine, auxiliary brushes on each side of one of said load brushes and insulated therefrom, anti-sparking windings, and means (.perative by current flowing between said auxiliary brushes for varying the excitation of said antisparking windings.

4. In a dynamo electric machine, an armature winding provided with a commutator, brushes on said commutator, anti-sparking windings connected in series with said brushes, auxiliary anti-sparking windings,'a resistance in series with said auxiliary windings, and means responsive to a difference of potential between heel and toe of any one of said brushes to insert and withdraw said resistance in the circuit of said auxiliary windings to vary their excitation.

5. In a dynamo electric machine, an armature winding provided with a commutator, brushes on said commutator. anti-sparking windings, auxiliary anti sparking windings, means for varying the cxcitation of said auxiliary windings in accordance with a diflerence of voltage {com hecl to too of one of said brushes, and means for varying the polarity of said auxiliary windings in accordance with the polarity of the voltage from heel to toe of one of said brushes.

6. In a dynamo electric machine, an armature winding provided with a commutator,

brushes on said commutator, commutating poles, windings on said poles connected in series with said armature winding, auxiliary winlings on said poles and means for varying the excitation of said auxiliary windings in accordance with a difference of poi tential from heel to toe of said brushes.

7. In a dynamo electric machine, an arma ture winding provided with a ci'unmutator, brushes carrying the load of said machine, auxiliary lfn'ushes on each side of one of said sparking windings connected in series with said armature winding. auxiliary antisparking windings. and means operative by current flowing between said auxiliary brushes for varying the excitation of said auxiliary windings.

8. In a dynamo electric machine, an armature winding provided with a commutator, lbrushes carrying the load current of sald 1 machine, auxiliary brushes on each side of i one of said main brushes and insulated l therefrom, commutating poles, windings on i said poles in series with said armature wind- 1 ing, auxiliary windings on said poles and 1 means operative by current flowing between said auxiliary brushes for varying the ex 1 citation of said auxiliary windings.

i 9. In a dynamo electric machine, an armai ture winding provided with a commutator, brushes on said commutator, anti-sparking windings, a resistance in series with said I main brushes and insulated therefrom. unt1. i

tator, brushes carrying the load current of said machine, auxiliary brushes on each side of one of said main brushes and insulated therefrom, commutating poles, windings on said poles connected in series with said load brushes, resistance in series with said auxiliary windings, and means operative by current flowing between said said auxiliary brushes for inserting and withdrawing said resistance in the circuit of said auxiliary windings to vary their excitation.

15. In combination a dynamo electric machine provided with armature coils, commuanti-sparking windings, and means responsive to a difference of potential between the heel and toe of any one of said brushes to insert and withdraw said resistance in the circuit of said anti-sparking windings to vary their excitation' 10. In a dynamo electric machine, an armature winding provided with a commutator, brushes on said commutator, commutating poles, windings on said poles connected in series with said brushes, auxiliary windings on said poles, a resistance in series with said auxiliary windings, and means responsiv'e to a difi'erence of potential between the heel and toe of any one of said brushes to insert and withdraw said resistance in the circuit of said auxiliary windings to vary their excitation.

11. In a dynamo electric machine, an armature winding provided with a commutator, brushes carrying the load current of l said machine, auxiliary brushes on each side I magnetic circuit for a coinmutating magnetic flux, a pair of auxiliary brushes bear- 1 ing on the commutator on opposite sides of one of the main brushes, and means responsive to the voltage across the auxiliary brushes for control ing the commutating flux.

16. In combination, adynamo-electric machine provided with an armature, commutator and main brushes and with commua' pair of auxiliary brushes bearing on the commutator on opposite sides of one of the main brushes, and a regulator responsive to the voltage across said auxiliary brushes, and adapted to control the an excitation of the commuta'ting poles.

17. In a dynamo electric machine, an armature winding provided with a commutater, brushes'ca'rryingthe load current of safidmachine, auxiliary brushes on each side of one of said main brushes, commutating poles, exciting windin s on said poles, auxilia'ry windings on sai poles and means operative by current flowing between said auxof one of said main brushes and insulated therefrom, anti-sparking windings, a resistance in series with said anti-sparking windings, and means operative by current flowing between said auxiliary brushes for inserting and withdrawing said resistance I in the circuit of said anti-sparking windings i to vary their excitation.

12. In a dynamo electric machine, armature winding provided with a commui tator, brushes carrying the load current of said machine, auxiliary brushes on each side of one of said main brushes and insulated v therefrom, anti-sparking windings connected in series with said load brushes, auxiliaryanti-sparking windings, a resistance in series with said auxiliary windings, and means operative by current flowing between said auxiliary brushes for inserting and Withdrawing said resistance in the circuit of said auxiliary windings to "ary their excitation.

13. In a dynamo electric machine, an armature windingprovided with a commutator, brushes carrying the load current of said machine, auxiliary brushes on each side of one of said main brushes and insulated therefrom, commutating poles, windings on said poles, a resistance inseries with said windingson said poles, and means operative by current flowing between said auxiliary brushes for inserting and withdrawing said resistance in the circuit of said windings on said poles to vary their excitation.

I tating poles,

said auxiliary winding y 18. In combination,a dynamo-electric machine provided with an armature, commutator and main brushes and with commutating poles, windings and connections for exciting said commutating poles, a pair of auxiliary brushes bearin on the commutator on opposite sides 0 oneo'i the main brushes, and a yibratory regul'ato'r reslpo'nsive to the voltage across said au'xi lary brushes and adapted to control the current in said windin In witness whereof, I'have hereunto set my hand this 22nd day October,

, JOSEPH L. B URNHAM. Witnesses:

14. In a d nam'o electric machine, an Hams ORF RD, armature win ing provided with a commu- BENJAMIN B. HULL.

Ooplej of this flatent ma as obtained for five cents each, by addressing the tlominissioner or mum.

' Washington, 1). c."

auxiliary windings on said poles, a

tator and brushes, and having a suitable ili'ary brushes for varying the excitation of 

